Property Changes/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim is napping in a deck chair next to a swimming pool. Moby approaches him carrying a watermelon. He drops the watermelon on Tim and it breaks into several pieces. TIM: Waah! Tim reads from a typed letter. TIM: Dear Tim and Moby, what's the difference between a physical change and a chemical change? From, Leo. A physical change happens when matter changes size, shape, or form. When that watermelon dropped, it changed from a round green melon into a pink and green mess of pieces. It's still watermelon. Just... ah... changed. Moby stomps up and down on the pieces of watermelon, smashing them. TIM: Another type of physical change is the change from one state of matter to another. Tim holds an ice cream sandwich. TIM: The ice cream in this thing was solid a minute ago, but it's changing to liquid faster than I can eat it! Tim's ice cream sandwich begins to melt. TIM: Melting ice cream is a quick physical change, but some physical changes take years and years to happen. Eight years ago, this patio was brand new. Over the years, some small cracks formed. Then water froze and expanded inside the cracks, making them even bigger. This change is called physical weathering, and it's caused by the effects of water and wind over time. An image shows the cracks in the patio tiles around the pool. Pop-up images illustrate the effects of water and ice as Tim describes them. TIM: Weathering is responsible for much of the shape of Earth's surface. Images show various types of land formations, including mountains, canyons, craters, and cracks. MOBY: Beep. Moby is on his knees, digging through the smashed watermelon with one hand. He finds a rusted toy car and hands it up to Tim. TIM: That must be left over from my cousin Freddie's visit. The rusty metal is actually an example of a chemical change. Iron in the metal reacts with oxygen in the air, forming a third substance that we call rust. An animation shows the toy car with no rust. Rust gradually forms as Tim explains the process. TIM: You know a chemical change has occurred when the substances that make up an object have been changed into other substances. Tim holds the rusted toy car. TIM: When sodium metal and chlorine gas come in contact with each other, they react, and the result is salt! Moby shakes salt onto a piece of watermelon. TIM: You wouldn't want to eat sodium or chlorine on their own. Both are very poisonous, but the salt crystals produced by this chemical reaction are found in every kitchen. Images show sodium, labeled Sodium, Na, and chlorine, labeled Chlorine, Cl, along with a beaker. The beaker smokes, illustrating a chemical reaction. An image shows a salt shaker, labeled, Table salt, NaCl. MOBY: Beep. TIM: Right, Moby, you can't always see chemical reactions. In fact, chemical reactions happen inside of you every day! Moby mashes some watermelon with his hand as Tim speaks. TIM: When food enters your body, it's broken apart by your teeth. That's a physical change, by the way. The chemical changes happen when the food is broken down by enzymes so nutrients can be delivered to cells that need them. You know that a chemical change has happened because your energy level increases in the hour or so after you eat. An image shows a side-view of a head. The teeth are shown chewing some food and the broken pieces are swallowed and end up in the stomach where a chemical reaction occurs. Tim's stomach growls. He puts a hand on it. TIM: Whoa. I guess I'm getting hungry! Moby picks up some mashed watermelon from the ground and hands it to Tim. MOBY: Beep. TIM: Um, no thank you. MOBY: Beep. Moby moves the mess slowly toward Tim's face. There are sticks, stones, and dirt mixed in with the mashed watermelon. TIM: No, actually, I was mistaken. I'm not really hungry at all! Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts